During the spring of 1803, Sellers trained with her father and learned to collect and prepare bird specimens with
arsenic. Sellers and her father remained in the city and worked on renovations to the museum. Yellow fever had been an
ongoing problem in Philadelphia since 1793. During the 1803 outbreak, Sellers worked for several months, copying
Latin binomials (following the
Linnaean system), English, and French common names from a handwritten "Book Catalogue", which had been prepared in 1795–1797 by
Palisot de Beauvois, onto wooden frames, which were then attached to the glass cases containing the mounted birds. On August 7, 1803, Charles wrote to his sons again: The Museum will now in a short time have the Catalogue in frames over each Box — Sophonisba has advanced so far, that I have now Taken out of the Room the Book Catalogue.Shortly after Sellers completed her "Catalogue in frames," Charles printed a summary of the bird collection in a pamphlet entitled
A Guide to the Philadelphia Museum (1804):There are now in this collection, perhaps all the birds belonging to the Middle, many of which likewise belong to the Northern and Southern States, and a considerable number from South America, Europe, Africa, Asia, New Holland, and the recently discovered islands of the South Seas. The number exceeds 760 [specimens] without the admission of any duplicates, contained in 140 cases. == Personal life ==